Clay Buchholz was expected to be on his way back to rejoining the Boston Red Sox starting rotation soon, but that was train of thought was derailed Thursday when Red Sox manager John Farrell announced because of lingering soreness, Buchholz's scheduled bullpen session this week was scratched.

The soreness was first reported by Buchholz during a bullpen session Sunday in Oakland. Buchholz thought about playing catch Tuesday in New York while making his appearance as a member of the American League All-Star team, but instead didn't touch a baseball and has not since Sunday.

"We have every intention and hope and outlook that he will resume pitching this season," Farrell said Thursday to reporters. "I wish I could give you an exact date, to be honest with you. And Clay would, too."

Buchholz underwent an MRI June 27 that revealed bursitis, not structural damage, in his right shoulder. After more rest, Farrell said Buchholz could potentially start thinking about a simulated game, then a rehab assignment. That's not the case anymore with his latest setback.

"There's no one more frustrated in this than Clay, and that needs to be made clear," Farrell said. "He's a strong competitor, he recognizes the situation we're in and he wants to be on the mound. That's the bottom line. But at the same time, his body's telling him one thing."

Buchholz has thrown 11 2/3 innings in two starts since May 22—when he first noticed the problem but attributed it to his toddler daughter sleeping on his shoulder—and has been diagnosed multiple times since with irritation of the AC joint and a strained trapezius muscle.

Farrell said Buchholz is not currently slated for an MRI, but he hopes the right-hander will be able to resume throwing on flat ground soon.

This could end up being a similar situation to 2011. That year, Buchholz went on the disabled list in June with a back problem. While trying to come back from what was not thought to be a serious injury, he was diagnosed with a stress fracture in his back in August and missed the rest of the season.

Before going on the disabled list this year, Buchholz went a perfect 9-0 with a 1.71 ERA in 12 starts.